Method and apparatus for applying plastic material to surfaces



March 18, 19 0. J. R. MACK 115L 4 METHOD AND APPARATUS FOR APPLYING PLASTIC MATERIAL TO SURFACES Filed Sept. 19, 1925 (II/II/I/II/IIIIII :NVENTQR M WM furnaces.

Patented Mar. 18, 1930 UNITED STATES PATENT oFFmE JOHN R. MACK, or cALDwELL,'NEw JERSEY, AssIeNon TO THE CARBORUNDUM'. cou- PANY, or NIAGARA FALLS, NEw YORK, A CORPORATION or PENNSYLVANIA ME'1HOD AND. APPARATUS FOR APPLYING PLASTIC MATERIAL TO Sl'iIBrFAC'fiIElS 1 Application filed September 19, 1925. Serial No. 57,432.

Thisinvention relates to a method and apparatus for spreading or spraying plastic materials such as cement, refractory coatings and the like over the surface of new or used 5 masonry or concrete structures, such as fur-.

or less uniform, relatively thin coating of plastic refractory cement to the interior thereof. It is common practice to do this by means of a brush or by hand troweling. For more efficient application, especially of large areas, mechanical devices for sprayin or coating the surfaces have been sought. guch machines or appliances in use at the present time are of two general classes. In one type,

commonly referred to as grouting machine's, the cement or plastic compositon is quite liquid and it is put into a tank from which it is-forced by hydraluic or pneumatic pressure. In the second type dry cement is transported to an air nozzle where it is mixed with a suitable amount of water.

The pressure devices, or grout machines, while in some cases satisfactory, have distinct disadvantages in that very liquid material is required for successful operation of the machine. When very liquid material strikes the wall or surface to be coated it does not adhere well because the excess water washes off the adhering cement. A further disadvantage of these pressure devices is the expense of making and maintaining-the relatively large high pressure tanks or containers into which the plastic material is put. 'llhehigh friction of thick plastic semi-liquids pr events the long distance spraying "of cementby this system,

and this is of a distinct disadvantage inlarge The second type of appliance or machine consists of a rather complex arrangement for transporting dry cement material through a W flexible tube to the nozzle where it is moistened with water and discharged. This device has been successfully used in some instances but requires large and complex mechanical devices for its operation. Furthermore, it is extremely diflicult to control, particularly to obtain the proper mixture of water and cement. No advantage can be taken in a machine of this type of the inherent plastic nature of the cement material, and with many materials complete moistening of the drycement cannot be attained in a device of this kind.

According to the present invention it is proposed-to use a sprayer operating on the ejector principle for spraying the material against the surface to be covered and for bringing the material from a source of supply to theejector.

The invention may be readily understood by reference to the accompanying drawings which illustrate one embodiment of my invention but to the particular construction of which the invention is not limited.

In the drawings Figure 1 is a side elevation of the entire assembly showing .the cement sprayer, the

fluid pressure supply pipe, the cement conduit and the source of plastic cement.

Figure 2 is a vertical section through the venturi at the receiving end of the cement tube.

Figure 3 is a longitudinal section through the spraying device. I

In the drawings ,5 designates an ejector nozzle having a properly restricted passage 5' therethrough. Secured to the nozzle is a post 6to which a handle 7 may be attached. The inner end of the nozzle 5 is screwed into a cement chamber 8 having a connection -9 thereon to which the cement tube may be attached and through which cement is delivered from a source of supply to the ejector. At the outer end of-the member 8 is a gland 10 through which a suitable fluid pressure nozzle 11 is slidably' passed. Thls nozzle 11, which is concentrically arranged in the member 8, terminates adjacent the inner end of of theejector nozzle 5. I have shown a screw- 12 threaded through a post 13 on the nozzle 11 and rotatably received in a lug 14. on the gland 10 for the purpose of adjusting the nozzle 11. Obviously any suitable mechanism for this purpose may,be substituted.

Secured to the connector 9 is a conduit 16 preferably of a flexible nature. A fluid pressure pipe 15 which is preferably flexible connects to the outer end of the fluid pressure nozzle 11. Conduit 15 may connect with a suitable source of compressed air or high pressure steam. I have found that the operation of the device is more effective if steam is used rather than compressed air. This is presumably due to the condensation of some of the steam in the ejector.

The lower end of tube 16 is preferably provided with a suitable terminal 17 through which cement may be passed from a container into the tube. It. has been found that the flow of cement through the tube is facilitated if the member 17 is in the form of a venturi. This is especially true if air is admitted to the venturi at the proper point. In Figure 2 I have shown ports 18 opening into the venturi at the throat thereof. These ports connect with an annular chamber 19 to which an air supply pipe 20 may connect. I have indicated the device 17 asbeing set in a pail or container 21 in which is a plastic ,mixture 22. The pipe 20 extends above the level of the cement in the pail. If necessary the pipe 20 may be connected with a source of compressed air.

When steam or other gas under pressure is passed through the nozzle 11 into the e ector nozzle 5 it induces a flow of cement from the chamber 8 into the ejector nozzle 5. This flow of cement may be sprayed against the wall of the furnace or other surface to be covered and if it is of a roper consistency it will adhere to such sur ace.

A very stiff plastic mixture may be used with the sprayer. i This is especially true where a Venturi type inlet tube 17 is used at the inlet terminal of the cement tube 16 and where such venturi is provided with suitably arranged air inlet ports. It has been found that a plastic mixture having considerabl less water may be used if air is admitte to the venturi as described. It is probable that where steam is used in the ejector that the expansion of the air pockets in the cement aids in the ejection of the cement from the nozzle of .the ejector.

The nozzle'11 may be adjusted toward or away from the ejector nozzle 5 depending on the consistency of the cement being spra ed or on the ressure of the steam or ot er expansive tiilid passing through nozzle 11. With extremely high pressure's the nozzle 11 may be retracted to induce a eater flowof cement. The nozzle 11 may e moved forwhere material being sprayed is comparatively stiff.

If desired the dischar e nozzle 5 may be extended to a considerab e length. In F igure 1 I have shown in dotted lines a removable flexible tubing at the discharge end of the ejector nozzle through which material may be forced. I find that with the pressure of steam of about 100 pounds an extension of four feet may be added to the discharge of the ejector nozzle and with pressures ranging between 200 and 300 pounds as much as thirty or forty feet can be added. In many cases it would be desirable to use a flexible hose connection which will permit the sprayer to be operated in any position so that coating may be put upon arches, upper parts of furnaces and inaccessible places where it is now impossible to apply cement even by using a trowel. In coatin a boiler wall'for example, the

cool for three of four'hours until the temperature is sufficient to permit a man to go inside the furnace. The temperature of the wall at such time may be between 300 to 400 degrees Fahrenheit' In coating the furnace wall a man starts at the top moving the sprayer back and forth and workin down the wall. The plastic material, pre erably silicon carbide cement, made from silicon carbide grain in which fire clay is added as a bond, is applied to a thickness of about one-half an inch. If desired a second coating of one-half inch thickness may be applied after waiting one hour. When the cement strikes the Wall a little excess water will frequently run out of the cement and flow down the wall. If too much water has been mixed with the cement, this excess water causes a washing away of the material applied, which is of course objectionable. Inv

order to properly carry out the invention, the cement should be mixed with water, preferably warm water, to a consistency of a thick mortar, such for instance as that used in plastering walls. The amount of water will vary according to the nature of the cement and the consistency of the mix desired and the water absorbing properties of the cement. At the proper consistency the cement should not flow or have a tendency to flatten out when heaped in a pile.

For other purposes a thinner cement may be used but a thin cement may only be used where a relatively thin coating is to be applied.

The entire device may be'transported as desired and the operator 'may hold the ward where the pressures are reduced or, cement of almost any consistency desired and it permits the cement to be mixed in proper quantities when and where desired.

While I have described and shown one specific construction of the invention it will be understood that I do not limit myself to the particular construction and arrangement shown. Neither is the use of the device limited to the specific purposes herein mentioned as it may be used for spreading plastic material over other structures than furnaces and the like and as desired.

I claim as my invention:

1. A cement sprayer including an ejector nozzle, a cement chamber at the inner end of the nozzle in alinement therewith, and a restricted fluid pressure nozzle passing through the cement chamber and having a divergent end' portion terminating adjacent the inner end of the ejector nozzle, said fluid pressure nozzle being adjustable in the cement chamber toward or away from the ejector nozzle, and means on the exterior of the sprayer for adjusting the said fluid pressure nozzle.

2. A cement sprayer including. an ejector nozzle, a cement chamber at the inner end of the nozzle in alinement therewith, a fluid pressure nozzle passing through the cement chamber and terminating adjacent the inner end of the ejector nozzle, said fluid pressure nozzle being slidably supported at one end of the cement chamber structure so that it may be moved toward or away from the ejector nozzle and means including a screw for adj usting the fluid pressure nozzle, substantially as described.

3. Apparatus for applying cement of a con- I sistency which substantially precludes washing, comprising a cement sprayer including an ejector, a suction pipe leading from the sprayer, a terminal at the free end of the suction pipe having a venturi therein, and means for admitting air to the'venturi, substantially as described.

4. Apparatus for applying cement of a consistency which substantially precludes washing, comprising a cement sprayer including an ejector, a suction pipe leading from the sprayer and through which cement is supplied to the ejector, an intake venturi at the terminal of the suction pipe, said venturi having an air inlet port adjacent the throat thereof, and an air pipe communicating with the air port, substantially as described.

- 5. Apparatus for applying cement of a consistency which substantially precludes washing, comprising a cement sprayer including an ejector, a suction pipe leading from the sprayer and through which cement. is supplied to the ejector, an intake venturi at the terminal of the suction pipe, said venturi having a plurality of ports adjacent the restricted portion thereof, an annular air supply passage connected with the several ports, and an air pipe connected with the air supply passage, substantially as described.

my hand.

6. The method of applying plastic material having a consistency sufficient to preclude a coating of plastic material having a con-.

sistency suflicient to preclude washing, which consists in diluting said plastic material with air at less than atmospheric pressure, then drawing the plastic material through a conduit by aspiration and projecting it on the surface by means of a jet of gas directed through a nozzle against the surface to be coated.

8. Apparatus for applying cement of a consistency which substantially precludes wash-.

ing, com rising a gas ejector, a suction pipe connecte to a low pressure region'within the ejector, a plastic cement container in which the suction pipe terminates, the terminal portion of the suction pipe in the container haw ing a flared end, a constriction at the narrow end of the flare, and a pipe connection from the constriction to the atmosphere.

In testimony whereof I have hereunto set JOHN R. 'MAOK; 

